The applicaton of newly developed phosphorylating reagents to the synthesis of oligodesoxyribo- and oligoribonucleotides, of phospholipids (e.g., cardiolipins), and of other biochemically significant phosphate esters will be continued. New and even more powerful phosphorylating reagents will be sought. Studies on the role of pentacoordinate phosphorus in the mechanism of action of enzymes related to phosphorus metabolism will be continued. Particular attention will be paid to practical syntheses of cyclic AMP and related naturally occuring and unnatural analogs of cyclic AMP.